. The use of PCR- based assays in clinical laboratories performing human leukocyte antigen (HLA) typing is growing rapidly. This has created a need for increasingly stringent standards for test validation and laboratory accreditation. However, there are currently no commercially available specific control HLA DNA standards for use with PCR or DNA probe-based test systems. Presently the most widely used HLA DNA typing methods utilize either sequence-specific primers (SSP) to PCR amplify specific HLA alleles or sequence-specific oligonucleotide probes (SSOP) to detect HLA alleles amplified using primers to conserved HLA gene sequences. Although these approaches have proved to be effective HLA typing techniques, the applicant argues that quality assurance remains a concern. The only approach currently available for monitoring the quality of individual primer pairs is to concurrently test control genomic DNA isolated from a panel of reference cell lines. However, maintenance of reference cell lines is labor intensive and costly. The overall goal of this Phase I proposal is to examine the feasibility of producing one set of DNA standards for use with SSP and SSOP HLA typing assays and to compare their performance to currently used reference cell genomic DNA standards. The specific aims are: 1) To construct a set of DNA standards for HLA-DRB typing; 2) To optimize the standards for use with SSP typing; and 3) To optimize the standards for use with SSOP typing.